[unreadable] Research on adult motivational profiles for substance use suggests that temperamental differences influence an individual's incentive for using drugs and alcohol. For example, adults who score high on sensation seeking are likely to abuse alcohol for its reward properties, whereas adults who score high on trait anxiety are likely to abuse alcohol for its anxiolytic effects. Although responses to alcohol cannot be measured directly in children, temperamentally based responses to reward and anxiety-inducing stimuli can be assessed through physiological measures collected during other incentive and aversive conditions. Psychophysiological measures that have proven useful in assessing temperamental traits include cardiac pre-ejection period (PEP), electrodermal responding (EDR), and respiratory sinus arrhythmia (RSA). Under appropriate stimulus conditions, PEP, EDR, and RSA can be used to index reward insensitivity, trait anxiety, and emotion dysregulation, respectively. Measuring PEP, EDR, and RSA will allow for physiological assessment of motivation and emotion regulation while children respond to reward and punishment. This will allow for the examination of the relations between reward insensitivity, trait anxiety, emotion dysregulation and the initiation and escalation of substance use in pre-adolescents with depression and conduct disorder. In addition, the interaction of both self report and physiological measures of temperament with social risk factors including coercive parenting, parental monitoring, and school bonding will be examined. [unreadable] [unreadable] [unreadable] [unreadable] [unreadable]